This patch was taken from NixOS
https://raw.githubusercontent.com/Mindavi/nixpkgs/1a737743a829746e48f4869ac517ff29c23c9d09/pkgs/tools/security/afl/qemu-patches/syscall-glibc2_30.diff
It is based on an unmerged patch against american-fuzzy-lop and was
never merged upstream because the author was unable to sign Google's CLA.
Based on https://github.com/google/AFL/commit/6c917e3d63a2a0685d58c3518524f9615b001893.patch

--- qemu-2.10.0-clean/linux-user/syscall.c	2020-03-12 18:47:47.898592169 +0100
+++ qemu-2.10.0/linux-user/syscall.c	2020-03-13 09:13:42.461809699 +0100
@@ -34,6 +34,7 @@
 #include <sys/resource.h>
 #include <sys/swap.h>
 #include <linux/capability.h>
+#include <linux/sockios.h> // https://lkml.org/lkml/2019/6/3/988
 #include <sched.h>
 #include <sys/timex.h>
 #ifdef __ia64__
@@ -256,7 +257,9 @@ static type name (type1 arg1,type2 arg2,
 #endif
 
 #ifdef __NR_gettid
-_syscall0(int, gettid)
+// taken from https://patchwork.kernel.org/patch/10862231/
+#define __NR_sys_gettid __NR_gettid
+_syscall0(int, sys_gettid)
 #else
 /* This is a replacement for the host gettid() and must return a host
    errno. */
@@ -6219,7 +6222,7 @@ static void *clone_func(void *arg)
     cpu = ENV_GET_CPU(env);
     thread_cpu = cpu;
     ts = (TaskState *)cpu->opaque;
-    info->tid = gettid();
+    info->tid = sys_gettid();
     task_settid(ts);
     if (info->child_tidptr)
         put_user_u32(info->tid, info->child_tidptr);
@@ -6363,9 +6366,9 @@ static int do_fork(CPUArchState *env, un
                mapping.  We can't repeat the spinlock hack used above because
                the child process gets its own copy of the lock.  */
             if (flags & CLONE_CHILD_SETTID)
-                put_user_u32(gettid(), child_tidptr);
+                put_user_u32(sys_gettid(), child_tidptr);
             if (flags & CLONE_PARENT_SETTID)
-                put_user_u32(gettid(), parent_tidptr);
+                put_user_u32(sys_gettid(), parent_tidptr);
             ts = (TaskState *)cpu->opaque;
             if (flags & CLONE_SETTLS)
                 cpu_set_tls (env, newtls);
@@ -11402,7 +11405,7 @@ abi_long do_syscall(void *cpu_env, int n
         break;
 #endif
     case TARGET_NR_gettid:
-        ret = get_errno(gettid());
+        ret = get_errno(sys_gettid());
         break;
 #ifdef TARGET_NR_readahead
     case TARGET_NR_readahead:
